I like the PR explanation. Is Charles had spent some of his money on some positive publicity, the X-Men would be loved by people other than the residents of San Francisco.

Then again, that's one of those stupid common sense things that make too much sense to use in a comic. Like the fact that Charles, Emma, and Warren could've tried using their billions of dollars to lobby Congress and slide some money under the table to get better treatment of mutants from the government. No way in hell a sentinel program would've passed if Professor X had spent more money bribing the right people.